Short-term memory is an important component of outpatient management of heart failure (HF). Many HF patients have short-term memory deficits, which can adversely impact management of their disease and dramatically increase morbidity and mortality. Injury in brain areas which control short-term memory have been reported in HF, with neural damage and symptoms (short-term memory loss, depression) similar to those seen in persons with thiamine deficiency. However, the associations between thiamine levels, brain injury (particularly of the mammillary bodies, which are important structures involved in short-term memory), and clinical measures of short-term memory have not been reported in HF. Therefore, the specific aims of this study are to: 1) Examine the associations between plasma thiamine levels, short-term memory (via the Digit Span Test), and mammillary body volumes (volumetric T1-weighted measures via magnetic resonance imaging [MRI]) in advanced (left ventricular ejection fraction [LVEF] <0.40;systolic dysfunction;dilated cardiomyopathy) HF patients;2) Examine the relationships between plasma thiamine levels, short-term memory, and mammillary body volumes and clinical characteristics (age, LVEF, body mass index, number of re-hospitalizations for HF in 6 months). Using a one-group, correlational design, 26 HF subjects will undergo structural MRI (T1-weighted), have blood drawn for plasma thiamine analysis, and have their short-term memory evaluated using the Digit Span Test (auditory version). Inclusion criteria for all subjects will be age of 40 years to 65 years, systolic dilated HF, and LVEF <0.40. Exclusion criteria for all subjects includes claustrophobia, presence of loose metal (for example, pacemakers, braces, implanted hearing aids, or embolic coils). MRI analysis will consist of volumetric measures (using T1) of the bilateral mammillary bodies of each HF subject. Statistical tests will consist of Pearson's correlations, Spearman's rho, and Chi-square with significance set at p <0.05. In summary, the overall purpose of this study is to identify associations between mammilary body brain structure injury, thiamine levels, and clinical evaluation of short-term memory in HF patients. Information on the association among these factors has important clinical implications in HF. Evaluation of short-term memory is important for both patient education and self-management strategies, as well as for assessment of the impact of HF management treatments and potential identification of new treatment strategies in this high risk patient population. PUBLIC HEALTH RELEVANCE: Heart failure afflicts over 5 million persons in the United States, and many of these patients have significant problems with their memory, which diminishes their capacity to manage their disease and increases morbidity and mortality. Thiamine (B1) is a water-soluble vitamin which can induce both heart failure and brain damage (particularly in the mammillary bodies). Unfortunately, the links among these factors are not clear in heart failure. Identification of the relationship between memory, thiamine, and mammillary body brain injury will enable clinicians to better assess and evaluate heart failure patients and to identify patient education and health care resources to optimize heart failure management of this high risk group.